Magnetic tape cartridges are widely used for data storage. A conventional magnetic tape cartridge comprises a base plate and a cover. Reel mounts are located on the base plate, on which tape reels are held in place. A magnetic tape is attached to two tape reels, and is wound around one or both of the reels. The reels are rotatable on the reel mounts, allowing the reels to transfer the commonly attached magnetic tape from one reel, acting as a supply reel, to the other reel, which acts as a takeup reel upon rotation. The tape travels a fixed path, from the tape supply reel to the takeup reel, about a pair of spaced corner pins.
A portion of the tape is exposed to the outside of the cartridge by means of an open bay portion which may comprise a door or other protective lid-type feature for protection of the tape when the cartridge is not in use. Between the bay portion and a side of the cassette, the tape extends over split post members which guide the tape to the bay portion.
When the cartridge is in use, the bay portion of the cartridge receives an external read/write device which sends data to be recorded onto a tape, or retrieves recorded information from the tape. The read/write device accomplishes this by entering the bay portion, and contacting the tape.
As the tape extends across the bay portion of the cartridge, moving from one reel to the other, the tension in the tape is the greatest when each reel is holding equal amounts of tape. However, when any one reel is holding more or less tape than the other reel, the tension in the tape can become insufficient for enabling continuous physical contact between the tape and the read/write device. This lack of tension in the tape, and in turn, lack of physical contact between the tape and the read/write device, causes the transfer of information between the two elements to fail. As a result, some or all of the information intended to be transferred will be missing upon playback or subsequent transferring of information.
Accordingly, there is a need to provide a magnetic tape cartridge in which a desired range of tension in the magnetic tape may be maintained. The range of tension must be such that is sufficient to enable complete and direct contact between a read/write device and the magnetic tape, thus ensuring accurate and complete transfer of information between the two elements.
There is also a need in the art for means for maintaining a desired range of tension in tape included in existing magnetic tape cartridges which otherwise fail to transmit information between the tape and the read/write device. The range of tension should be sufficient to enable complete and direct contact between the read/write device and the magnetic tape, thus ensuring accurate and complete transfer of information between the two elements.